Electrocardiogram Sensor Research Articles

Flexible Piezoresistive Sensor Patch Enabling Ultralow Power Cuffless Blood Pressure Measurement

Noninvasive and real‐time cuffless blood pressure (BP) measurement realizes the idea of unobtrusive and continuous BP monitoring which is essential for diagnosis and prevention of cardiovascular diseases associated with hypertension. In this paper, a wearable sensor patch system that integrates flexible piezoresistive sensor (FPS) and epidermal electrocardiogram (ECG) sensors for cuffless BP measurement is presented. By developing parametric models on the FPS sensing mechanism and optimizing operational conditions, a highly stable epidermal pulse monitoring method is established and beat‐to‐beat BP measurement from the ECG and epidermal pulse signals is demonstrated. In particular, this study highlights the compromise between sensor sensitivity and signal stability. As compared with the current optical‐based cuffless BP measurement devices, the sensing patch requires much lower power consumption (3 nW) and is capable of detecting subtle physiological signal variations, e.g., pre and postexercises, thus providing a promising solution for low‐power, real‐time, and home‐based BP monitoring.

Remote health monitoring system for detecting cardiac disorders.

Remote health monitoring system with clinical decision support system as a key component could potentially quicken the response of medical specialists to critical health emergencies experienced by their patients. A monitoring system, specifically designed for cardiac care with electrocardiogram (ECG) signal analysis as the core diagnostic technique, could play a vital role in early detection of a wide range of cardiac ailments, from a simple arrhythmia to life threatening conditions such as myocardial infarction. The system that the authors have developed consists of three major components, namely, (a) mobile gateway, deployed on patient's mobile device, that receives 12-lead ECG signals from any ECG sensor, (b) remote server component that hosts algorithms for accurate annotation and analysis of the ECG signal and (c) point of care device of the doctor to receive a diagnostic report from the server based on the analysis of ECG signals. In the present study, their focus has been toward developing a system capable of detecting critical cardiac events well in advance using an advanced remote monitoring system. A system of this kind is expected to have applications ranging from tracking wellness/fitness to detection of symptoms leading to fatal cardiac events.

Biomedical Data Management and Processing -A New Framework

The integration of information from biomedical devices is of fundamental importance for effective medical diagnosis. In this sense, the present work aimed to develop a new framework able to manage and process biomedical data in real time. The major advantage of the proposed solution is the ability to add new medical devices and integrate their results with the existing ones. The devices tested include brainwave sensors, a baropodometric treadmill and a biomedical kit composed of a patient position sensor (accelerometer), glucometer, body temperature, blood pressure, pulse and oxygen in blood, airflow, galvanic skin response and electrocardiogram sensors. From the tests conducted, it can be concluded that the proposed framework is robust, accurate and fast, and can manage and process large volumes of data in real time. Customizable graphs can be built from the electroencephalogramsignals acquired during patient gait, which can be analyzed based on barographic image registration. Finally, it can be concluded that the framework is quite promising to be used to assist medical diagnosis and improve and accelerate the treatment of patients.

Simple method for adaptive filtering of motion artifacts in E-textile wearable ECG sensors.

In this paper, we have developed a simple method for adaptive out-filtering of the motion artifact from the electrocardiogram (ECG) obtained by using conductive textile electrodes. The textile electrodes were placed on the left and the right wrist to measure ECG through lead-1 configuration. The motion artifact was induced by simple hand movements. The reference signal for adaptive filtering was obtained by placing additional electrodes at one hand to capture the motion of the hand. The adaptive filtering was compared to independent component analysis (ICA) algorithm. The signal-to-noise ratio (SNR) for the adaptive filtering approach was higher than independent component analysis in most cases.

Performance Evaluation of New-Generation Pulse Oximeters in the NICU: Observational Study.

This crossover observational study compares the data characteristics and performance of new-generation Nellcor OXIMAX and Masimo SET SmartPod pulse oximeter technologies. The study was conducted independent of either original equipment manufacturer (OEM) across eleven preterm infants in a Neonatal Intensive Care Unit (NICU). The SmartPods were integrated with Dräger Infinity Delta monitors. The Delta monitor measured the heart rate (HR) using an independent electrocardiogram sensor, and the two SmartPods collected arterial oxygen saturation (SpO2) and pulse rate (PR). All patient data were non-Gaussian. Nellcor PR showed a higher correlation with the HR as compared to Masimo PR. The statistically significant difference found in their median values (1% for SpO2, 1 bpm for PR) was deemed clinically insignificant. SpO2 alarms generated by both SmartPods were observed and categorized for performance evaluation. Results for sensitivity, positive predictive value, accuracy and false alarm rates were Nellcor (80.3, 50, 44.5, 50%) and Masimo (72.2, 48.2, 40.6, 51.8%) respectively. These metrics were not statistically significantly different between the two pulse oximeters. Despite claims by OEMs, both pulse oximeters exhibited high false alarm rates, with no statistically or clinically significant difference in performance. These findings have a direct impact on alarm fatigue in the NICU. Performance evaluation studies can also impact medical device purchase decisions made by hospital administrators.

MO‐F‐CAMPUS‐J‐02: Human Implanted Micro Bio Chip for Real‐Time Atrial Fibrillation Monitoring with Wireless Power Transmission

Purpose:There are numerous medical problems whose treatment requires the constant monitoring of vital signs from several body organs. In this study, a micro‐sized implantable electrocardiogram (ECG) sensor for personal heart disease monitoring was developed, as such devices generally provide a high diagnostic yield.Methods:An op‐amp amplifies an input electrical potential to the level desired by the user and produces an output potential augmented to this intended level. For this study an instrumentation amplifier was fabricated using op‐amps and configured to amplify micro‐fine ECG signals by a factor of about 100 using a band‐pass filter (BPF). The proposed ECG sensor has a current consumption of about 11 mA and a noise generation inversely proportional to the length of the wireless communication antenna inside the sensor. The packaging materials selected must be biocompatible to avoid causing inflammation or necrosis of human tissues. In addition, a near‐field wireless power transmission system and the medical Implant Communication Service (MICS) was used as a communications and power protocol. MICS operates in the frequency range of 402–405 MHz and is normally used for communication between body‐worn monitoring systems and implants.Results:A pig was used as a sensor‐implanted animal model because the animal's physiological characteristics are similar to those of humans. An incision was made between the left 5th–7th ribs and separated using blunt dissection to a depth of 4 mm under the skin. From the experiments, we successfully monitor the ECG with wireless communication and wireless power transmission.Conclusion:This study demonstrated that the use of a quasi‐permanentECG employing a double loop coil‐shaped magnetic resonance‐type wireless power transmission system sensor eliminates the need for surgical replacement.

Driver’s ECG Signal Detection and Transmission by Impulse-Radio-Based Human Body Communication Technology

In this study, we developed a wearable electrocardiogram (ECG) sensor with human body communication (HBC) tech- nology for vital data transmission in a car. The ECG signals were modulated with wideband pulse signals between 10 and 60 MHz based on an impulse radio (IR) scheme, which provides a data rate as high as 1.25 Mbps. To apply the HBC-based wearable ECG in a moving car, we employed a moving average algorithm to reduce the noises produced in the received ECG signals due to the car's movement. As a result, we conrmed a real-time ECG transmission of driver in the moving car with a reasonable accuracy.

Energy Optimization of ZigBee Based WBAN for Patient Monitoring

This paper proposes an energy efficient wireless telemonitoring scenario of cardiac patients through ZigBee, based on variable duty cycle being rendered to sensors. In an intra hospital telemedicine scenario, Electrocardiogram (ECG) signals of patients are acquired through ECG sensor nodes having transmission capability and these ECG signals are received by Personal Digital Assistant (PDA) kept at nursing station through ZigBee network. ECG signals are further transmitted to Doctor's PDA. If the duty cycle is varied as per the load or number of active sensors, total energy consumed in idle mode can be avoided and total energy consumed by sensors is reduced hence increasing total network lifetime. This paper, comparatively analyzes the energy efficiency of ZigBee sensors with different percentage of duty cycle on the basis of energy consumption parameter under variable load conditions. The matrices used in performance evaluation are energy consumption in transmit mode, energy consumption in received mode and energy consumption in idle mode using Qualnet 5.0.2 simulator.

Development of An Unconstrained Capacitive Electrocardiogram Sensor for Automobile Driving

Development of An Unconstrained Capacitive Electrocardiogram Sensor for Automobile Driving

The electrocardiogram as an electronic filter and why ac circuits are important for pre-health physics students

We present a general physics laboratory exercise that centres around the use of the electrocardiogram sensor as an application of circuits and electronic signal filtering. Although these topics are commonly taught in the general physics classroom, many students consider topics such as alternating current as unrelated to their future professions. This exercise provides the motivation for life science and pre-health majors to learn concepts such as voltage, resistance, alternating and direct current, RLC circuits, as well as signal and noise, in an introductory undergraduate physics lab.

A 300-mV 220-nW event-driven ADC with real-time QRS detection for wearable ECG sensors.

This paper presents an ultra-low-power event-driven analog-to-digital converter (ADC) with real-time QRS detection for wearable electrocardiogram (ECG) sensors in wireless body sensor network (WBSN) applications. Two QRS detection algorithms, pulse-triggered (PUT) and time-assisted PUT (t-PUT), are proposed based on the level-crossing events generated from the ADC. The PUT detector achieves 97.63% sensitivity and 97.33% positive prediction in simulation on the MIT-BIH Arrhythmia Database. The t-PUT improves the sensitivity and positive prediction to 97.76% and 98.59% respectively. Fabricated in 0.13 μm CMOS technology, the ADC with QRS detector consumes only 220 nW measured under 300 mV power supply, making it the first nanoWatt compact analog-to-information (A2I) converter with embedded QRS detector.

Editorial (Thematic Issue: Computer Networks and Communications in Multimedia and Information Technology)

Networks and communications are the infrastructure on which multimedia and information technologies are built. There are a vast number of networking techniques that depend on the type of multimedia and information technology applications that the network is designed to facilitate. This issue concerns recent communication technologies for transmission, compression, security, and expression of a diverse range of data. In this issue, we discuss how networking techniques are applied in the areas of health, business and transport, which require multimedia and information. This special issue should provide insight into the design of networking technology for applications ranging from sensor networks to broadband networks. The first contribution, published by T. Huynh and W. Hwang, concerns throughput optimization in multicast wireless networks. Various applications, including mobile multimedia, airports, smart homes and audio–video conferencing, require multicast communication to deliver large volumes of data to a group of users. It is important that multiple users receive the same data simultaneously via a reliable transmission network. In this paper, the authors describe an analytical model used to characterize throughput optimization that guarantees the reliability of transmission. In the second contribution, G. Chung and H. Kim introduce digital yarns (or conductive yarns), which enable data transmission. These yarns are particularly interesting in that they can form a crucial element of wearable computing devices, creating a body area network. In particular, smart clothes woven from both ordinary and digital yarns are promising for future applications in many areas of our everyday lives. In this paper, the authors describe the concept of healthwear, with electro cardiogram (ECG) sensors connected using digital yarns. The third contribution is from J. Shim and J. Ko, and discusses the design and implementation of an Ethernet–xBee bridge module for wireless sensor networks, termed Eth2Bee. A wireless sensor network consists of spatially distributed autonomous sensors that monitor physical or environmental conditions, such as temperature, sound or pressure. Eth2Bee can connect wireless networks to the Internet and provide a low-cost gateway technology for the Internet of Things (IoT). The fourth contribution concerns social networking. Yao Meng discusses the use of social media to promote physical activity. In particular, social influence is an effective method of effecting change in attitudes and behavior. She reports a field-study whereby participants used a walking promotion system, which implements workout groups and competition to encourage physical activity. She found that these workout groups, and the associated competition, had a significant effect on the likelihood of participants to use the system. The final contribution to this special issue concerns mobile secure transmission. With the rapid growth of the threedimensional (3D) content industry, 3D mobile secure transmission has recently become important, and digital watermarking and cryptographic protocols have been evaluated. Mobile 3D content, e.g., in mobile 3D games, often requires content security for copyright protection and piracy tracing of 3D graphic models. S. Lee and K. Kwon present a multiple watermarking scheme that uses the anonymous Buyer-Seller watermarking protocol. The method described in this paper can enable copyright protection and measure to prevent illegal copying. Consequently, I sincerely hope that this special issue will be enjoyable and useful to the readers.

Driver fatigue and drowsiness monitoring system with embedded electrocardiogram sensor on steering wheel

Real time driver health condition monitoring system with drowsiness alertness was proposed. A new embedded electrocardiogram (ECG) sensor with electrically conductive fabric electrodes on the steering wheel of a car was designed to monitor the driver's health condition. The ECG signals were measured at a sampling rate of 100 Hz from the driver's palms as they stay on a pair of conductive fabric electrodes located on the steering wheel. Practical tests were conducted using an embedded ECG sensor with a wireless sensor node, and their performance was assessed under non-stop 2 h driving test. The ECG signals were measured and transmitted wirelessly to a base station connected to a server PC in personal area network environment. The driver's health condition such as the normal, fatigued and drowsy states was analysed by evaluating the heart rate variability in the time and frequency domains.

Compressed Sensing Analog Front-End for Bio-Sensor Applications

In a conventional bio-sensor, key signal features are acquired using Nyquist-rate analog-to-digital conversion without exploiting the typical bio-signal characteristic of sparsity in some domain (e.g., time, frequency, etc.). Compressed sensing (CS) is a signal processing paradigm that exploits this sparsity for commensurate power savings by enabling alias-free sub-Nyquist acquisition. In a severely energy constrained sensor, CS also eliminates the need for digital signal processing (DSP). A fully-integrated low-power CS analog front-end (CS-AFE) is described for an electrocardiogram (ECG) sensor. Switched-capacitor circuits are used to achieve high accuracy and low power. Implemented in 0.13 μm CMOS in 2×3 mm2, the prototype comprises a 384-bit Fibonacci-Galois hybrid linear feedback shift register and 64 digitally-selectable CS channels with a 6-bit C-2C MDAC/integrator and a 10-bit C-2C SAR ADC in each. Clocked at 2 kHz, the total power dissipation is 28 nW and 1.8 μW for one and 64 active channels, respectively. CS-AFE enables compressive sampling of bio-signals that are sparse in an arbitrary domain.

Radiation Efficiency-Improvement Using a Via-Less, Planar ZOR Antenna for Wireless ECG Sensors on a Lossy Medium

The critical issues involving severe radiation efficiency degradations during wireless electrocardiogram (ECG) health monitoring sessions are addressed by devising a monolithic zeroth-order resonance (ZOR) antenna. The presented antenna consists of a composite right/left-handed (CRLH) structure that is realized on a single, planar surface of the flexible printed circuit board (PCB) without the use of any via-holes. This significantly alleviates the complexity and fabrication cost involved with vertically polarized antennas with monopole-like radiation patterns, which are important factors in consumer electronics. Moreover, this letter investigates the practical issues associated with effects of the in-house designed ECG device circuit board, feeding mechanism with the RFIC, as well as the polycarbonate chassis. The finalized antenna is less than 0.12λ×0.08λ in total horizontal dimension with zero height profile. Measurement confirms the presented antenna features more than 30% radiation efficiency across 80 MHz bandwidth when completely integrated within the ECG sensor device and placed on the human body phantom.

Implementation of ECG QRS complex detector for Body Sensor Networks

This paper aims to present a mathematical morphological method to remove baseline wandering and background noise is removed from original ECG signal. Then the multipixel modulus accumulation is employed to act as a low-pass filter to enhance the QRS complex and improve the signal-to-noise ratio. The performance of the algorithm is evaluated with standard MIT-BIH arrhythmia database. Corresponding power and area efficient VLSI architecture is designed and implemented on a commercial nano-FPGA. High detection rate and high speed demonstrate the effectiveness of the proposed detector. Index Terms: Body sensor networks (BSNs), electrocardiogram (ECG) sensor, field-programmable gate array (FPGA), mathematical morphology, QRS detection, very-large-scale integration (VLSI) architecture

A Level-Crossing Based QRS-Detection Algorithm for Wearable ECG Sensors

In this paper, an asynchronous analog-to-information conversion system is introduced for measuring the RR intervals of the electrocardiogram (ECG) signals. The system contains a modified level-crossing analog-to-digital converter and a novel algorithm for detecting the R-peaks from the level-crossing sampled data in a compressed volume of data. Simulated with MIT-BIH Arrhythmia Database, the proposed system delivers an average detection accuracy of 98.3%, a sensitivity of 98.89%, and a positive prediction of 99.4%. Synthesized in 0.13μm CMOS technology with a 1.2V supply voltage, the overall system consumes 622nW with core area of 0.136mm (2), which make it suitable for wearable wireless ECG sensors in body-sensor networks.

Is This the Future of Medical Technology?

Is This the Future of Medical Technology?

Remote Patient Monitoring Based on ZigBee: Lessons from a Real-World Deployment

This work presents detailed experimental performance results from tests executed in the hospital environment for Health Monitoring for All (HM4All), a remote vital signs monitoring system based on a ZigBee® (ZigBee Alliance, San Ramon, CA) body sensor network (BSN). Tests involved the use of six electrocardiogram (ECG) sensors operating in two different modes: the ECG mode involved the transmission of ECG waveform data and heart rate (HR) values to the ZigBee coordinator, whereas the HR mode included only the transmission of HR values. In the absence of hidden nodes, a non-beacon-enabled star network composed of sensing devices working on ECG mode kept the delivery ratio (DR) at 100%. When the network topology was changed to a 2-hop tree, the performance degraded slightly, resulting in an average DR of 98.56%. Although these performance outcomes may seem satisfactory, further investigation demonstrated that individual sensing devices went through transitory periods with low DR. Other tests have shown that ZigBee BSNs are highly susceptible to collisions owing to hidden nodes. Nevertheless, these tests have also shown that these networks can achieve high reliability if the amount of traffic is kept low. Contrary to what is typically shown in scientific articles and in manufacturers' documentation, the test outcomes presented in this article include temporal graphs of the DR achieved by each wireless sensor device. The test procedure and the approach used to represent its outcomes, which allow the identification of undesirable transitory periods of low reliability due to contention between devices, constitute the main contribution of this work.

An Optical Fiber-Based Gating Device for Prospective Mouse Cardiac MRI

Prospective synchronization of MRI acquisitions on living organisms involves the monitoring of respiratory and heart motions. The electrocardiogram (ECG) signal is conventionally used to measure the cardiac cycle. However, in some circumstances, obtaining an uncorrupted ECG signal recorded on small animals with radio frequency (RF) pulses and gradient switching is challenging. To monitor respiratory motion, an air cushion associated with a pressure sensor is commonly used but the system suffers from bulkiness. For many applications, the physiological gating information can also be derived from an MR navigated signal. However, a compact device that can simultaneously provide respiratory and cardiac information, for both prospective gating and physiological monitoring, is desirable. This is particularly valid since small volume coils or dedicated cardiac RF coil arrays placed directly against the chest wall are required to maximize measurement sensitivity. An optic-based device designed to synchronize MRI acquisitions on small animal's respiratory and heart motion was developed using a transmit-receive pair of optical fibers. The suitability of the developed device was assessed on mice ( n = 10) and was based on two sets of experiments with dual cardiac and respiratory synchronization. Images acquired with prospective triggering using the optical-based signal, ECG, and the pressure sensor during the same experiment were compared between themselves in the first set. The second set compared prospective technique using optical-based device and ECG to a retrospective technique. The optical signal that was correlated to both respiratory and heart motion was totally unaffected by radiofrequency pulses or currents induced by the magnetic field gradients used for imaging. Mice heart MR images depict low-visible motion artifacts with all sensors or techniques used. No significant SNR differences were found between each series of image. Full fiber-optic-based signal derived from heart and respiratory motion was suitable for prospective triggering of heart MR imaging. The fiber optic device performed similarly to the ECG and air pressure sensors, while providing an advantage for imaging with dedicated cardiac array coils by reducing bulk. It can be an attractive alternative for small animal MRI in difficult environments such as limited space and strong gradient switching.